Super Best Audio Friends

The evolution of the original irreverent and irrelevant and non-authoritative site for headphone measurements, i.e. frequency response graphs, CSD waterfall plots, subjective gear reviews. Too objective for subjectivists; too subjective for objectivists

Special thanks to @rhythmdevils for taking us back to memory lane. The AMB Gamma 2 DAC was a wonderful sounding DAC during the infancy of headphone audio. It was available as DIY only; however assembled models could easily be found for sale. The DAC uses the old Wolfson chip, which is a good sounding part, but tonally it could sound all other the place. The AMB Gamma 2 DAC implementation has a bold sound with a minimum of digital nasties. The tone was its primary selling point. It was not the most resolving or nuanced sounding DAC however.

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I wanted to showcase this DAC because this is an example of how marketing practices prevailed over engineering. For those who actually thought NWAVGUY was a master engineer, looking to save us all from bad measuring gear by developing the ODAC, there was already one DAC design readily available from his arch-nemesis AMB or Ti Kan with arguably better performance. Those of us who have met Ti Kan know what an outstanding and humble dude he is. If there was any DAC that should have been the ODAC, the AMB Gamma 2 should have been it.
Measures x1000 times worse than Magni 3+. Sounds cool, where do I sign up?
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The Vali 2+ is different from the Vali 2 in these respects.
  • More present highs - less dark
  • More lively, more resolving, more engaging similar to the Vali 1 (in retrospect, Vali 2 was a step and a half forward, but a step back).
  • I think the Vali 1 still has a small edge in immediacy, but the Vali 1 also has some issues with the super tube microphonics and highish distortion which is audible, but in a pattern that indicates euphonic distortion.
I'm not going to wax poetic on the Vali 2+. However, I do think it would be fun to take measurements using different tubes. Why not? Folks rolled all sorts in tubes in the Vali 2s of old, including rare exotic tubes that cost x4 the amp.
I have so much gear in the queue that I decided that I would do a stream of consciousness review to get you the goods on the DAC2541 as I go along instead of making everyone wait. I know that there is a lot of interest here.

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After a day of warm-up, the DAC2541 is ungodly good. Those who want an oversampling DAC with a modicum of inherent warmth, but no outright warmpoo; an honest, but smooth and not-in-your-face top-end; and microdynamics and PRaT that grabs your very soul by the balls, then this is it. I had some idea of how this DAC may have sounded like given my experience with Soekris' prior generation of DACs, but my expectations have been exceeded.

1100 EUR. Wow, just wow.
Per @spwath, we shall conduct a poll on the Harman Curve. This one is public.
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Read this for more technical explanation from @Vtory: https://www.superbestaudiofriends.org/index.php?threads/harmon-curve-poll-public.10130/#post-325059
Alright? Here we go. Headband badge is crooked. A nitpick, yes, but notable. There are also some marks on the edges that I have circled in red. This seems to suggest either poor plastic moulding or damage during assembly. Maybe they had to replace the badges? They almost look like pry marks. Things only get worse from here.
[​IMG]
Synopsis: Measurements of steady state signals indicate of a certain type of R2R design. Low level signals are impressive. The steady state measurement results at higher levels are not earth shattering, but they confirm nothing is wrong, and are more than good enough to not have any bearing on subjective sound quality.

Rockna Wavelight DAC
1kHz sine 0dbFS
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-90dbFS
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The short story is that HE5XX was released, a few FR measurements were dropped, and then suddenly it seemed that almost everyone assumed that the HE5XX was a reskin of the Deva and got their panties in a twist. How dare Drop reskin a Deva and call it an HE5XX? How dare Drop invoke the name of the glorious HE-500 and use the Deva drivers! Surely Drop is deceiving us and we must call them out on this for their shamelessness!

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Will, Drop's product guy, attempted to explain that there actually was some effort to create a custom headphone with the HE5XX (of course from HFM's parts bin and bag of know-how), but his explanation satisfied no one. Of course not! Once everybody on the Internet has been wronged (whether rightly or wrongly), the pitchforks must come out. In times such as this, steadier minds must prevail.

So let's proceed with various analyses. I don't know the total answer quite yet, I so will be doing this along with you.
Elekit has been on my radar since I got the DIY bug not too long ago. I've also heard only great things about Elekit amps and the building experience, but there wasn't much impressions out there for their relatively new-ish amp TU8800, their singled-ended pentode amp with a f**k ton of tube rolling options (both blessing and a curse I guess) due to various power mode and two connection modes (Triode and Ultralinear mode). I didn't think too much of the UL mode until I heard @ChaChaRealSmooth 's one off Eddie Current's Ultralinear amp. My god, that amp made my JAR650 into a slam cannon with ZERO Sennheiser veil. It's definitely one of my favorite synergistic amps I've heard with the HD6x0 series. Unless I could somehow trick Chacha into selling me his amp, my chances of obtaining that amp was close to zero. This is where Elekit comes in.

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Holy f**k $220? I'm so glad Drop is back to its old self where the deal is so fricking good that I have to give them my money. TBH, I thought this was going to be priced at $399 - "as a deal" - the old HE-500s were what? $699. What it comes down to is that in my mind, the PPP (proper price point for performance), which I can be a bit stingy or tight on, was $400. $220 beats this significantly. The downside for this price is that we will have to wait.

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A lot of people are going to be happy that HiFiMan has brought these back from the dead. There's been a segment of hobbyists who have been itching to get that of that old school sound (HE-6, HE-5, HE-500). HiFiMan, while initially saying that bringing them back was out of the question, has been steadily releasing remasters of them in the past few years. Customer demand is hard to ignore. Looks like Drop went all in with HFM on the HE5XX, and that's a good thing because all of sudden, its super affordable. The appeal with the OG HFMs was their timbre and slam. The newer HFMs with their thinner membranes and wannabe STAX sensibilities didn't always appeal to the old schoolers. Despite sounding "faster", many models exhibited steely, splashy, or plasticky timbre, lacked slam, or exhibited bouncy-bouncy effect in the lows. Now I wouldn't say that these HFM remasters go totally back in time to the OG sound, but they do straddle the line between the OG and new HFM sound. It's a good compromise in my opinion.
In light of this discussion where I was accused of being all like: "dude trust me as it’s surprisingly lacking in any sort of spec whatsoever from a site priding itself on measurements and objectiveness and the initial pitch feels intentionally vague" and requests from @Boops, @atomicbob and others out of curiosity in regards to this amp both subjective and objective, I figured I'd offer up some objective measurements and also discuss the history of this amp. Note that all variants of the EC Studio are sold out and it is unlikely that Craig will ever make one again.

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I really won't get too much into how it sounds, other than maybe a few tidbits related on how this came to be. This amp came to be from a project Leviathan that never really took off, or at least took off in another direction. Basically one day, some guy bought some high-end Tango amorphous core interstage and output transformers and asked Craig to build a 2A3 amp out of it. The special thing about this amp was that an interstage transformer was used in lieu of a interstage coupling cap. There was an attempt to build this amp for Changstar folks, but it turned out that Tango went out of business (they are back in business again) and this project went kaput. The Studio amp came to be as a result of using Tribute nano-crystalline core interstages and Cinemag outputs with a tertiary winding (a McIntosh design from long ago).
Despite high proclamations by YouTubers, it turns out that the HD560S is much ado about nothing - at least to most of the audience here. One step forward and one step back, at least when compared to the old HD558. Compared to the established standards, the HD600/HD650, the HD560 is one step forward and two steps back.

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I can't recall exactly, but I thought maybe the HD558 may have had very slightly angled drivers. Regardless, the HD560S takes the cake and pulls of a really impression of the HD800's headstage. Very impressive! From my limited experience so far, the headstage is closer to the HD800 end of the spectrum than the HD6xx end. Unfortunately, this is where the good news stops. The frequency response takes a hit. The HD558, the predecessor to the HD560S, had small an upper-mid peak. This wasn't particularly obtrusive and made a lot of music sound more energetic. @ultrabike owned the HD558 for years and was perfectly happy with it before finally upgrade to the HD600...
Notable highlights:
Liquid Gold X (LAuX) has been optimized for balanced operation. It provides great performance Single Ended but clearly best performance is attained in balanced mode. If contemplating this amplifier, balanced headphone cables will prove a wise choice. LAuX falls squarely in the transparent design camp. Attributes of low output impedance, low residual noise, low distortion, high bandwidth, fast transient response definitely contribute to extraordinarily clean performance.

Listening picture:
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Typical of Cavalli designs bandwidth is quite wide, DC to > 500KHz with 30R load and DC to > 600KHz with 300R load.
Dynamic Range is greater than 113 dB relative to 0 dBu in balanced mode.
Note particularly the exceptionally low IMD for all two tone tests, not just 19+20 KHz which is impressive.
Note too, the fast square wave response transitions times do not ring, also very impressive.